Multistation working machine with working unit coupling and stairstep guides

ABSTRACT

An index plate (9) is moiunted on a shaft (7) which is supported against axial displacement on a machine frame (1) and is stepwise rotatably drivable, said plate carrying clamping devices (10) arranged around the shaft and each intended for one workpiece (11). On either side of the indexing plate (9) a unit carrier (20) is arranged axially displaceably of the unit carriers (20) towards the indexing plate (9) into a stop position and for displacement of the unit carriers (20) away from the indexing plate a displacement drive (31) is associated with each of said carriers. The two unit carriers (20) are guided solely on the shaft (7) and are supported on the machine frame (1) only against rotation. Each of the unit carriers (20) comprises a crown wheel type serration or toothing (29) which faces the indexing plate (9) and which in the stop position of the respective unit carrier is in torque-transmitting engagement with a crown wheel type serration (28) formed on the indexing plate (9) and defining the stop position. Arranged on each of the unit carriers (20) are a plurality of working units (45). For executing feed movements the working units (45) are guided displaceably on the associated unit carriers (20) and each connected to a feed unit (53) activatable in the stop position thereof.

This application is a divisional of application Ser. No. 145,563, filedJan. 19, 1988, U.S. Pat. No. 4,833,763.

In a multistation working machine known from DE-AS 1,205,795 two toolheadstocks are guided axially displaceably on a machine frame. A shaftis radially mounted in the two headstocks and is further secured againstaxial displacement by bearing brackets belonging to the machine frame.Arranged on the shaft are an indexing plate and on either side thereofan adjustable stop nut which limits the displaceability of the adjacentheadstock towards the indexing plate. In each of the two tool headstocksa plurality of working units is fixedly installed and the tool spindlesof said units are driven via central gears and intermediate gears byelectric motors likewise incorporated in the tool headstocks. Noprovision is made for axial displacement of the tool spindles withrespect to the tool headstocks incorporating them. On the individualtool spindles tools corresponding to the shape of the workpieces to beworked are secured in such a manner that during the movement of theassociated tool headstock they work towards the indexing plate andterminate their work at the instant in which the respective toolheadstock reaches its stop position.

This known machine permits the production of workpieces of high accuracyonly when the machine frame is configured so that the guides formedthereon for the two headstocks at any temperature occurring in operationextend rectilinearly and in alignment with each other and guide the twoheadstocks free of play. Furthermore, the drive for the stepwiseexecuted rotations of the shaft must be extremely accurate and free ofplay. Finally, the stop nuts must be free of play and have stop facesextending exactly perpendicularly to the shaft so that the headstockshave an exactly defined position thereon. All these requirements can bemet, if at all, only with a great production expenditure and only for alimited life of the machine.

The problem underlying the invention is therefore to further develop themultistation working machine so that it permits a high working accuracyduring a long life with less expenditure for its manufacture.

According to the invention a multistation working machine comprises

a shaft which is supported against axial displacement on a machine frameand rotationally drivable stepwise,

an indexing plate which is secured to the shaft and carries arrangedround the shaft clamping or chucking devices each for a workpiece,

two unit carriers which are each arranged on one side of the indexingplate and are axially displaceable with respect to the shaft,

a plurality of working units which are each arranged on one of the unitcarriers, and

displacement drives for displacing the unit carriers towards theindexing plate into a stop position and for displacing the unit carriersaway from the indexing plate,

the two unit carriers being guided solely on the shaft and supported onthe machine frame only against rotation,

each of the unit carriers comprising a crown wheel type serration whichfaces the indexing plate and which in the stop position of therespective unit carrier is in torque-transmitting engagement with acrown wheel type serration formed on the indexing plate and defining thestop position, and

the working units for executing feed movements are displaceably guidedon the associated unit carrier and are each connected to feed unitactivatable in the stop position thereof.

This achieves that the indexing plate and the two unit carriers form inthe clamped together state a rigid unit in every respect in which thelocation accuracy of the unit carriers with respect to the indexingplate and thus also with respect to each other is independent ofinfluences of other components of the machine, in particular oftemperature-dependent deformations of the machine frame.Temperature-dependent deformations of the unit carriers themselves alsoremain substantially without influence on their position and locationwith respect to the indexing plate. The individual working units executetheir feed movements with respect to this rigid unit. The starting andend points of the feed movements are governed solely by the feed unitsand cannot be falsified to any extent of practical significance bylocation inaccuracies of the unit carriers with respect to the indexingplate.

Due to the rigid clamping of the unit carriers with respect to theindexing plate bending moments produced by cutting forces are kept awayfrom the shaft so that the latter can be made of small diameter withoutthis impairing the working accuracy of the machine. Any torsion of theshaft between the indexing plate and a drive for the stepwise executedrotation thereof also has no influence on the working accuracy of themachine because the rotational angular position which the indexing plateassumes with respect to the unit carriers in the stop position thereofis defined solely by the crown wheel type serrations.

DE-AS 2,129,515 discloses the use of crown wheel type serrations in anindexing plate machine which comprises an indexing plate which ismounted in a machine frame and is adapted to be raised and lowered andin the raised position is rotatable stepwise about a central shaft.Workpiece receiving means are mounted with play on the indexing platearound the central shaft parallel to the latter. Said workpiecereceiving means each comprise a crown wheel type serration which onlowering of the indexing plate each engage into a complementary crownwheel type serration arranged stationarily on the machine frame. Theindexing plate is resiliently yieldable in its outer rim carrying theworkpiece receiving means with respect to a force clamping said platedownwardly along its central axis so that all the crown wheel typeserrations associated with each other in pairs on the workpiecereceiving means and on the machine frame can come simultaneously intomutual agreement.

In contrast, in the embodiment of the present invention described it isof significance that the two axially movable unit carriers are centredwith respect to the indexing plate without any participation of themachine frame via in each case a pair of complementary crown wheel typeserrations and are clamped or braced with respect to said indexing plateto form a rigid unit.

In a preferred further development of the embodiment of the inventiondescribed the unit carriers are each guided on the shaft by twobearings, of which at least the bearing which is nearer the indexingplate has a bearing play so that the respective unit carrier in its stopposition is centred with respect to the indexing plate solely by theintermeshing crown wheel type serrations. The unit carriers are thusorientated in position with respect to the shaft by the bearings only intheir position remote from the indexing plate and during the movement upto the start of the mutual engagement of the associated serrations. Asthe serrations come into mutual engagement they take over this centeringso that in effect any position inaccuracies of the shaft with respect tothe indexing plate and of the bearings with respect to the unit carriersare then no longer of any consequence.

Furthermore, the invention is preferably further developed in that theshaft is divided in the middle and comprises two flanges to which theindexing plate is secured and that the crown wheel type serrations arearranged with radial spacing around said flanges. This gives aparticularly rigid clamping of the indexing plate between the twoworking units.

For resetting to different workpieces the machine known from DE-AS1,205,795 requires a considerable amount of setting-up time. Ifworkpieces are to be machined which differ considerably from thepreviously machined workpieces then depending on the nature of thesedifferences a modification of the machine may be necessary which goesbeyond the abilities of the average qualified setter and can be carriedout at acceptable costs, if this is possible at all, only by speciallytrained personnel of the machine manufacturer.

It is therefore a further problem underlying the invention to furtherdevelop a multistation working machine in such a manner that it caneasily and rapidly be set up for different working tasks.

This problem is solved according to the invention by a multistationworking machine comprising

an indexing plate which is mounted on a machine frame and rotatablydrivable stepwise about the axis thereof,

a plurality of clamping devices for each workpiece which are arranged onthe indexing plate about the axis,

at least one unit carrier which is movable along the axis out of aretracted position into a stop position and

a plurality of working units which are arranged on the unit carrier andeach comprise a tool spindle,

the working units being guided displaceably each on an axis-parallelguide on the associated unit carrier and being individuallyexchangeable, and

each working unit being coupled by a rapidly releasable coupling to afeed unit which is secured to the respective unit carrier and after thereplacement of the associated working unit by another working unit beingcouplable to the latter in the same manner.

This makes it possible in simple manner to replace entire working unitswith tool spindle and tool. Since the feed units can remain on themachine particularly short resetting times result, especially since as arule no modifications need be made to the connections for the powersupply to the feed units.

It is particularly advantageous for each feed unit to have a thrust rodwhich is arranged coaxially with the tool spindle of the associatedworking unit. If the tool spindle itself is not to execute feedsparallel to the axis of the indexing plate but instead either the toolspindle as a whole is arranged radially or part thereof is to beradially advanceable, it is convenient for the thrust rod of the feedunit to be arranged coaxially with a hollow shaft preceding the toolspindle of the associated working unit.

The shortening of the resetting times which can be achieved with theinvention is particularly great when each working unit has associatedtherewith a drive unit which on replacement of the working unit alsoremains on the machine. It is then not necessary as a rule to make anymodifications to the connections for the power supply to the drive unitseither.

It is further advantageous for each drive unit to be mounted axiallyadjustably on the housing portion of the unit carrier to which theassociated feed unit is also secured. Alternatively, the drive units canbe mounted on the machine frame; this may be more convenient when thedrive units are particularly heavy.

It is further advantageous when all the feed units and the unit carriercarrying them have associated therewith a common control which allowsthe feed units to execute their feed movements in each case aftercomplete movement of the unit carrier towards the indexing plate andtheir return movements in each case overlapping in time with themovements of the unit carrier away from the indexing plate. The divisionof the necessary movements amongst the unit carrier or carriers on theone hand and the working units on the other makes it possible to shortenidle times in the overlapping movements away from the indexing plate.

For this purpose the machine according to the invention is preferablyfurther developed in that the feed units are hydraulic piston-cylinderunits which are connected to a fluid conduit for slow feed movements viaa multiway valve and an adjustable flow regulator and for fast returnmovements directly via the multiway valve.

In the machine according to the invention the guides for the workingunits may be arranged in star manner around the axis about which theindexing plate is rotatable. In such an arrangement with a givendiameter of the indexing plate the constructional space available forthe guides and the working units displaceable on them is however verylimited so that the guides cannot be made as robust as would bedesirable in view of the high stresses by high cutting forces occurringin operation or in view of the frequent replacement of the workingunits.

To overcome this restriction as well the invention provides amultistation working machine comprising

an indexing plate which is mounted on a machine frame and is rotatablydrivable by means of a shaft stepwise about the axis thereof,

a plurality of clamping devices each for a workpiece which are arrangedon the indexing plate around the axis,

at least one unit carrier which is arranged around the shaft and

a plurality of working units which each have a tool spindle and arearranged on the unit carrier in such a manner that the geometrical axesof said tool spindles each form a generatrix of an imaginary cylindercoaxial with the indexing plate and the shaft,

the working units each being displaceably guided on an axis-parallelguide on the associated unit carrier and

the guides for at least one group of working units whose tool spindlessucceed each other directly on the imaginary cylinder are arranged onthe unit carrier like steps of stairs adjacent each other.

In this manner it is possible to accommodate on the or each unit carrierrobustly dimensioned guides with working units guided thereon in acompact and nevertheless easily accessible manner.

This arrangement is preferably further developed in that of every threeguides belonging to a group the two outer guides lie in a common planecloser to the axis of the indexing plate and the third centre guide liesin a plane remoter from the axis.

With a view to good accessibility of the guides and also easy removal ofchips forming in the machining it is finally expedient for two groupseach of three guides to be arranged in V-shaped manner on each side ofthe axis.

An example of embodiment with further details of the invention will bedescribed hereinafter with the aid of schematic drawings, wherein:

FIG. 1 shows a vertical axial section through a machine according to theinvention split for space reasons into a left part in FIG. 1a and aright part in FIG. 1b,

FIG. 2 is the cross-section II--II of FIG. 1b,

FIG. 3 is a circuit diagram with very simplified details of FIG. 1a,

FIG. 4 shows details from the right part of FIG. 1a,

FIG. 5 shows details from the left part of FIG. 1b,

FIG. 6 shows details from the upper part of FIG. 1b.

The machine illustrated comprises a machine frame 1 which is made upsubstantially of a machine table 2 and two bearing pedestals or brackets3 and 4 rigidly mounted thereon. In the two bearing pedestals 3 and 4 ashaft 7 is mounted by means of an antifriction bearing arrangement 5 and6 respectively. The shaft 7 comprises a horizontal axis A and is securedagainst axial movements at the bearing bracket 4 but can move axiallywith respect to the bearing bracket 3; as a result, axial stresses areavoided even with different thermal expansions of the machine table 2and the shaft 7. The shaft 7 is divided approximately in the centre ofits length; the two half shafts thereby formed each have a flange 8which is screwed to an annular indexing plate 9. The indexing plate 9comprises a plurality, ten in the example illustrated, of clampingdevices 10 which are offset with respect to each other by uniformangular intervals and each intended for a workpiece 11. Each of theclamping devices 10 is actuable by means of a hydraulic piston-cylinderunit 12 which is supplied with hydraulic fluid from a connecting piece13 at the left end of the shaft 7 via axial conduits 14 and 14' and adistributor 15. The distributor 15 is arranged in the overall hollowshaft 7 and secured to a rod 16 which in turn is secured to a bracket 17projecting away from the bearing pedestal or bracket 4 and therebysecures the distributor 15 against rotation and axial displacement. Theclamping devices 10 and piston-cylinder units 12 are of usual design andconsequently need not be explained in detail.

The shaft 7 together with the indexing plate 9 rigidly mounted thereonis rotationally drivable stepwise through the angular interval betweenevery two adjacent clamping devices 10, in the example of embodimentillustrated in each case through 36°, from a stepping motor, notillustrated, via a stationarily mounted worm 18 and a worm wheel 19meshing therewith and rigidly mounted on the shaft 7. This rotary driveis also of usual construction and thus need not be explained in detail.A unit carrier 20 is axially displaceably guided on the shaft 7 oneither side of the indexing plate 9. Each of the unit carriers 20comprises an axially inner housing part 21 with respect to the indexingplate 9, a centre housing part 22 and a cover-like outer housing part23. The centre housing part 22 engages over a portion of the associatedbearing bracket 3 or 4 without restricting the axial displaceability ofthe respective unit carrier 20. Sliding bearings 24 and 25 ensure theaxial displaceability of the unit carrier 20 and of these bearings atleast the axially inner sliding bearing 24 adjacent the indexing plate 9has a play unusually large for machine tool guides of the order ofmagnitude of about one tenth of a millimetre.

To prevent the unit carrier 20 rotating on the shaft 7 or with thelatter an axis-parallel rod 26 is secured to the centre housing part 22and extends with radial clearance through a hole 27 in the associatedbearing bracket 3 or 4. The radial clearance is of the order ofmagnitude of about 2 mm so that the pairing of the rod 26 with the hole27 cannot perform any guide function whatever in the true sense.

At both end faces of the indexing plate 9 a respective crown wheel typeserration 28 is formed; such crown wheel type serrations arestandardized and also known under the designation Hirth serration. Thecrown wheel type serrations 28 are worked directly into the indexingplate 9 but may alternatively be rigidly mounted thereon as separatecomponents. Each of said crown wheel type serrations 28 has associatedtherewith a complementary crown wheel type serration 29 at the oppositeend face of the adjacent unit carrier 20. The crown wheel typeserrations 29 are formed in the example illustrated on a robustdish-shaped component 30 which is rigidly screwed to the axially innerhousing part 21 of the respective unit carrier 20 and carries theassociated sliding bearing 24. The crown wheel type serrations 28 and 29have an external diameter which is scarcely less than that of theindexing plate 9 and have an internal diameter which is considerablygreater than the external diameter of the flanges 8.

As long as the associated crown wheel type serrations 28 and 29 are outof engagement, as shown in FIG. 1a, because of the play in the slidingbearing 24 the respective unit carrier 20 is guided only approximatelyconcentrically to the shaft 7. When the unit carriers 20 are pushedtowards each other the crown wheel type serrations 28 each form a stoplimiting this displacement. To the extent and at the rate at which thecrown wheel type serration 29 of each unit carrier 20 comes intoengagement with the associated crown wheel type serration 28 on theindexing plate 9, as shown in FIG. 1b, the guide by the sliding bearings24 at the shaft 7 becomes ineffective and the unit carriers are centredsolely and very accurately with respect to the indexing plate 9.

At the end of their axial displacement towards each other the two unitcarriers 20 are clamped together with the indexing plate 9 to form arigid unit. Although the axially outer sliding bearings 25 still supportthe unit carriers 20 at the shaft 7, any accuracies in said supportingare however of no significance because machining operations take placeonly in the immediate vicinity of the indexing plate 9.

A displacement drive 31 is associated with each of the two unit carriers20 for the axial movements thereof towards the indexing plate 9 and forclamping to said plate and for the movements away from the indexingplate. Each displacement drive 31 includes a cylinder 32 which is formedwithin the shaft 7 and which is bordered by two stationary annular walls33 and 34, and an annular piston 35 arranged between said walls andrigidly connected by a tube 36 to the outer housing part 23 of theassociated unit carrier 20. Each of the two cylinders 32 is connected onone side of the associated piston 35 to passages 37 and 38 which arealternately fed from a fluid conduit P via a pressure relief valve, amultiway valve 40 and the connecting piece 13 or relieved via themultiway valve 40 to a return conduit T.

The fluid conduit P is connected via a pressure accumulator, notillustrated, of usual design to the pressure side of a hydraulic pumpwhich is also not illustrated and which furnishes a pressure of forexample 100 bar. The return conduit T is connected to a tank. The volumeof the pressure accumulator is so large that the displacements of theunit carriers 20 can take place mainly in quick feed or quick return.The multiway valve 40 is constructed as proportional valve and controlsthe displacements of the associated unit carrier 20 in such a mannerthat the carriers reach their end positions with greatly reduced speed.

Associated with each of the two unit carriers 20 are two stationaryinductive switches 41 and 42. The switch 41 ensures on proximation ofthe associated unit carrier 20 to the indexing plate 9 that theassociated multiway valve 40 switches to slow feed. The switch 42ensures on proximation of the associated unit carrier 20 to its endposition remote from the indexing plate 9 that the associated multiwayvalve 40 switches to slow return.

The switch 41 for the left unit carrier 20 illustrated in FIGS. 1a and 3is connected in series with a corresponding switch, not illustrated, forthe right unit carrier 20 illustrated in FIG. 1b. On return of the unitcarriers 20 these two switches 41 together effect that the indexingplate 9 is indexed further in each case through 36° when the two unitcarriers 20 have plate been moved away from the indexing plate to suchan extent that their crown wheel type serrations 29 are free of thecrown wheel type serrations 28 of the indexing plate 9. The furtherindexing of the indexing plate 9 also depends on inductive switches 43which are mounted on the unit carriers 20. These switches 43 and furtherswitches 43' also mounted on the unit carriers 20 will be explainedfurther below.

Each of the two unit carriers 20 has on its axially inner housing part21 a plurality of guides 44, six in the example illustrated, whichextend parallel to the axis A and are constructed to axiallydisplaceably guide one working unit 45 in each case The nature andnumber of the necessary working units 45 depends on the type ofmachining to be carried out on the workpieces 11. According to FIG. 2all the guides 44 of the unit carrier 20 illustrated therein and in FIG.1b are equipped with a working unit 45.

As shown in FIGS. 1b and 2 the working units 45 may each comprise aslide 46 which is guided at the associated guide 44 and on which a lowparallelepipedic housing 47 is adjustably mounted. Mounted in thehousing 47 is a tool spindle 48 which is parallel to the axis A andwhich at its end facing the indexing plate 9 carries a chuck 49 forclamping a tool, for example a drill bit 50 and at its other end iscoupled by a quick release coupling 51 to a thrust rod 52 of a feed unit53. The thrust rod 52 is arranged coaxial with the associated toolspindle 48. In the example illustrated each thrust rod 52 is a pistonrod and the associated feed unit 53 is a hydraulic piston-cylinder unit.

All the feed units 53 are mounted on the centre housing part 22 of thesame unit carrier 20 on whose inner housing part 21 the associatedworking unit 45 is guided axially displaceably. Although the feed units53 are basically replaceable they usually remain in place when theassociated working unit 45 is refitted or replaced for differentmachining tasks. The couplings 51 permit a rapid exchange of the workingunits 45 and are so designed that in operation they can transmit axialforces between the working spindle 48 and the associated thrust rod 52without the latter being entrained in rotation.

A drive unit 54 is further associated with each machining unit 45. Thedrive units 54 each have a motor 55 which is mounted via a setting means56 axially adjustably on the centre housing part 22 of the associatedunit carrier 20 and is connected via a transmission 57, for example aflat belt drive, to the associated working unit 45 to drive the toolspindle 48 thereof.

As illustrated in simplified form in FIG. 3 each of the feed units 53 isconnected via a two-way valve 58 to the fluid conduit P and the returnconduit T. Between the two-way valve 58 and the chamber of the feed unit53 which is subjected to pressure for advancing the associated workingor machining unit 45 a flow regulator 59 is disposed with which a checkvalve 60 is connected in parallel. In the return between the two-wayvalve 58 and the return conduit T there is a pressure-relief valve 61.

This hydraulic circuit achieves that the feed unit 53 illustrated inFIG. 3--and each correspondingly connected feed unit--imparts to theassociated working unit 45 feed or advance movements with low speedadjustable at the associated flow regulator 59 and return movements ofhigher speed. The two-way valve 58 is controlled jointly with themultiway valve 40 in such a manner that the return movements of the feedunits 53 and thus also of the associated working units 45 each takeplace completely or at least to a major part during the movements of theunit carriers 20 away from the indexing plate 9. The return speed ofeach working unit 45 is thus the sum of the return speeds of theassociated feed unit 53 and the associated unit carrier 20. Feed orinfeed movements produced by the feed units 53 do not however take placeuntil the unit carriers 20 move towards the indexing plate 9 and havebeen clamped to the latter to form a rigid block by the forces of thecentral piston 35.

Each of the feed units 53 cooperates on its return with one of theswitches 43 in such a manner that the latter emits a signal when therespective feed unit has reached an intermediate position with respectto the associated unit carrier 20. Only when such a signal has beenemitted by all the switches 43 does the movement of the unit carriersaway from the indexing plate 9 take place. If thereafter the switches 41have also emitted signals the indexing plate 9 can index further. Duringthe indexing the feed units 53 move further away from the switchingplate 9 into a position in which they actuate the associated switch 43'.In response to the signal of the latter the unit carriers 20 are againclamped to the meanwhile further indexed indexing plate 9 and theworking units 45 then carry out their feeds.

The movements of each feed unit 53 parallel to the axis A are alsoutilized to cause movements of an associated working unit 45 or partsthereof in other direction, for example radially. An example of this isillustrated in the upper part of FIG. 1a. The feed unit 53 indicatedthere is mounted like all the other feed units on the centre housingpart 22 of the associated unit carrier 20 in such a manner that itsthrust rod 52 extends parallel to the axis A and can thus exert onlyaxis-parallel forces. The thrust rod 52 is coupled via the associatedquick release coupling 51, which is simplified in this case, to a rack62 which is displaceably guided parallel to the axis A within a hollowshaft 63 in a pillar 64.

The pillar 64 is fixedly clamped to one of the guides 44 of the leftunit carrier 20. The rack 62 meshes with a pinion 65 which in turnmeshes with a rack 66 radially guided in the pillar 64. Via a furtherpinion 67 mounted in the pillar 64 the rack 66 drives the slide 46 ofthe associated working unit 45. Said slide being guided in this caseradially displaceably on the pillar 64. The tool spindle 48 of saidworking unit 45 is driven by the associated drive unit 54 via the hollowshaft 63 and an intermediate shaft 68 likewise radially mounted in thepillar 64. Said working unit 45, together with its pillar 64, can bejust as easily exchanged as all the remaining working units.

A further working unit 45 which performs a radial infeed motion isillustrated in FIG. 1b at the bottom and in FIG. 5. The slide 46 of theworking unit 45 therein is fixedly clamped directly to the associatedguide 44 of the right unit carrier 20 and the housing 47 is fixedlyclamped on the slide 46. On the tool spindle 48 of said working unit 45a tool holder 69 is disposed which is adapted for radial infeed andwhich carries a recessing tool 70. The thrust rod 52 of the associatedfeed unit 53 is coupled to a tube 71 which is connected to the toolspindle 48 for rotation therewith and via a coarse thread pairing 72 toa shaft 73. In this manner feed and return movements, extending parallelto the axis A, of the feed unit 53 illustrated at the bottom right inFIG. 1b are transformed via the coarse-pitch pair 72 to relativerotations of the shaft 73 with respect to the working spindle 48. Theshaft 73 is secured to a cam carrier 74 which is rotatably mounted onthe tool spindle 48 and controls the radial feed movements of the toolholder 69.

The guides 44 parallel to the axis A may be arranged in star mannerround the hollow shaft 7 at equal distances apart and from the axis A onthe one or other unit carrier 20 or on both carriers. It is however morefavourable when the guides 44, as illustrated in FIG. 2, are arranged instaircase manner in groups of three guides so that the two outer guidesof each group of three guides lie in a plane B1 having a relativelysmall spacing from the axis A whilst the centre guide of each group ofthree guides 44 lies in a plane B2 parallel to the plane B1 and having alarger spacing from the axis A.

In FIG. 2 a dot-dash circle concentric with the axis A indicates animaginary cylinder C on which lie both the geometrical axes of theworkpieces 11 clamped in the clamping devices 10 of the indexing plate 9and the geometrical axes W of the tool spindles 48 of all the workingunits 45 illustrated in FIG. 2. This illustration shows that the centreguide of each group of three guides 44 is arranged symmetrically withrespect to a diametrical plane D; said plane D contains the axis A ofthe indexing plate 9 and the axis W of the tool spindle 48 which isassociated with the respective centre guide. The two outer guides of thesame group of three guides 44 and the associated working units 45 aswell as the feed units 53 and drive units 54 are arranged as mirrorimages with respect to the diametrical plane D. The common plane B1 ofthe two outer guides and the plane B2 of the centre guide of each groupof three guides extend at a right-angle to the associated diametricalplane D.

Since as mentioned the indexing plate 9 carries ten uniformly angularlyspaced clamping devices and is rotatable stepwise through in each case36° , ten stations S1 to S10 are associated therewith and each workpiece11 clamped in a clamping or chuck device 10 passes consecutively throughsaid stations. In the station S1 after each indexing step of theindexing plate 9 a workpiece 11 is clamped in the clamping devices 10.Said workpiece is then machined successively in the stations S2 to S4.Work can also be carried out in the station S5; for example, in thelatter the working unit illustrated at the top right in FIG. 1a can bearranged which is equipped with a drill bit 50 radially aligned withrespect to the axis A. Further machinings take place in the stations S6to S8. In the station S9 the clamping device 10 which has arrived thereis opened and in the station S10 the finished workpiece 11 is ejected.

Since therefore the stations S1, S9 and S10 are in any case notavailable for machining workpieces it is convenient as illustrated inFIG. 2 to arrange the guides 44 in V manner in two groups each of threeguides 44.

I claim:
 1. Multistation working machine comprisingan indexing plate (9)which is mounted on a machine frame (1) and rotatably drivable about theaxis (A) thereof, a plurality of clamping devices (10) for eachworkpiece (11) which are arranged on the indexing plate (9) about theaxis (A), at least one unit carrier (20) which is movable along the axis(A) out of a retracted position into a stop position and a plurality ofworking units (45) which are arranged on the unit carrier (20) and eachcomprise a tool spindle (48), the working units (45) being guideddisplaceably each on an axis-parallel guide (44) on the associated unitcarrier (20) and being individually exchangeable, and each working unit(45) being coupled by a rapidly releasable coupling (51) to a feed unit(53) which is secured to the respective unit carrier (20) and after thereplacement of the associated working unit (45) by another working unitbeing coupled to the latter in the same manner.
 2. Multistation workingmachine according to claim 1, each feed unit (53) comprising a thrustrod (52) which is arranged coaxially with the tool spindle (48) of theassociated working unit (45).
 3. Multistation working unit according toclaim 1, each feed unit (53) comprising a thrust rod (52) which isarranged coaxially with a hollow shaft (63) preceding the tool spindle(48) of the associated working unit (45).
 4. Multistation workingmachine according to claim 1, each working unit (45) having associatedtherewith a drive unit (54) which on replacement of the working unit(45) also remains on the machine.
 5. Multistation working machineaccording to claim 4, each drive unit (54) being mounted axiallyadjustably on a housing portion (22) of the unit carrier (20) on whichthe associated feed unit (53) is also mounted.
 6. Multistation workingmachine according to claim 1, all the feed units (53) and the unitcarriers (20) carrying them having associated therewith a common controlwhich allows the feed units (53) to execute their feed movements in eachcase after complete movement of the unit carrier (20) towards theindexing plate (9) and their return movements in each case overlappingin time with the movements of the unit carrier (20) away from theindexing plate (9).
 7. Multistation working machine according to claim6, the feed units (53) being hydraulic piston-cylinder units which areconnected to a fluid conduit (P) for slow feed movements via a multiwayvalve (58) and an adjustable flow regulator (59) and for fast returnmovements directly via the multiway valve (58).
 8. The multistationworking machine according to claim 1 and which includes a shaft (7)rotatably drivable stepwise about the axis (A) and connecting theindexing plate (9), and wherein the tool spindles (48) are arranged onthe unit carriers (20) so that the geometrical axes (w) formed by thetool spindles (48) each form a generatrix of an imaginary cylinder (c)coaxial with the indexing plate (9) and the shaft (7), and the guides(44) for at least one group of working units (45) whose tool spindles(48) succeed each other directly on the imaginary cylinder (c) beingarranged on the unit carrier (20) in step-wise fashion adjacent eachother.
 9. Multistation working machine according to claim 8, of everythree guides (44) belonging to a group the two outer guides lying in acommon plane (B1) closer to the axis (A) of the indexing plate (9) andthe third centre guide lying in a plane (B2) remoter from the axis (A).10. Multistation working machine according to claim 9, two groups eachof three guides (44) being arranged in V-shaped manner on each side ofthe axis (A).